The present application relates to methods and apparatuses for measuring the properties of an emulsified drilling fluid.
Drilling fluids are often used to aid the drilling of wellbores into subterranean formations, for example, to remove cuttings from the borehole, control formation pressure, and cool, lubricate and support the bit and drilling assembly. Typically, the drilling fluid, which is more commonly referred to as “drilling mud” or “mud,” is pumped down the borehole through the interior of the drill string, out through nozzles in the end of the bit, and then upwardly in the annulus between the drill string and the wall of the borehole. During the ascent, some of the mud congeals, forming a cake on the exposed face of the wellbore, for example, to prevent the mud from being lost to the porous drilled formation. In addition, the pressure inside the formation can be partially or fully counterbalanced by the hydrostatic weight of the mud column in the wellbore. Since the mud has a variety of vital drilling functions, it must accordingly have comparable and reliable capabilities. In the oil and gas industry, it can be important to precisely determine the characteristics and chemical compositions of drilling fluids circulating into and out of subterranean hydrocarbon-bearing formations. However, drilling fluids are often circulated through the wellbore several times where the drill cuttings, leak-off, and the like can change the composition of the drilling fluid.
Many drilling parameters, such as measured depth, string rotary speed, weight on bit, downhole torque, surface torque, flow in, surface pressure, downhole pressure, bit orientation, bit deflection, and the like, can be made available in real-time. However, the composition of the drilling fluid, which can be critical to effective hydraulic modeling and hole cleaning performance, is not readily available in real-time. Ascertaining the composition of the drilling fluid typically requires a direct measurement by a technician (or “mud engineer”). The on-site mud engineer, for example, typically has numerous other responsibilities in his/her daily routine and, therefore, cannot provide a constant stream of drilling fluid composition to a monitoring center. In addition, taking and/or generating such measurements are time consuming and inherently susceptible to human error.